Abnormal Parasympathetic Vagal Function in Patients with Spasmodic Dysphonia

doi:10.1059/0003-4819-100-4-491

Abnormal Parasympathetic Vagal Function in Patients with Spasmodic Dysphonia

Dallas, Texas

Abstract

Gastric vagal function was assessed in 15 patients with spasmodic dysphonia by measuring gastric acid output in response to sham feeding. Patients secreted significantly less acid than controls (p < 0.001). Cardiac vagal function was assessed in 11 patients by measuring heart rate during deep respiration and also during and after Valsalva maneuver. Patients with spasmodic dysphonia had a significantly reduced fluctuation of heart rate during deep respiration (sinus arrhythmia). The expiratory to inspiratory R-R interval averaged 1.08 ± 0.08 (mean ± SD) in patients and 1.22 ± 0.10 in controls (p < 0.005). The ratio of tachycardia during Valsalva maneuver to bradycardia after Valsalva manuever was also lower in patients than in controls (p < 0.005). The auditory brainstem response was abnormal in 11 of 15 patients. Our results show either a central brainstem abnormality or several cranial nerve abnormalities in some patients with spasmodic dysphonia.

Article and Author Information

▸From the Dallas Veterans Administration Medical Center; the Department of Internal Medicine, University of Texas Health Science Center at Dallas; and Callier Center for Communication Disorders, University of Texas at Dallas; Dallas, Texas.
Grant support: in part by grants AM 16816 and NS 18276 from the National Institutes of Health, a Veterans Administration Merit Review, the Perkin Foundation, the Ariel Medical Foundation, and organized research grant AA 6495-7D from the University of Texas at Dallas.
▸Requests for reprints should be addressed to Mark Feldman, M.D.; Associate Chief of Staff for Research and Development (151), Dallas Veterans Administration Medical Center; Dallas, TX 75216.